Presentation on theme: "An Overview of Nutrition"— Presentation transcript:
1 An Overview of Nutrition Chapter 1An Overview of Nutrition
2 Chapter ObjectivesIdentify the six classes of nutrients and determine which are energy-yielding nutrients.List four factors that affect our food choices.Explain why meeting nutrient needs by eating a well-balanced diet is a healthier choice than relying on supplements.Describe the steps of the scientific method.Discuss the three different types of research that scientists can use to test their hypothesis.List several factors to consider when obtaining nutrition information on the internet.
3 Overview of Nutrition Nutrition Foods Diet Science of foods and the substances they contain, their actions within the bodyFoodsfrom plants or animal sourcesProvide energy and nutrientsUsed by the body for maintenance, growth, and repairDietThe foods one consumes.The quality of which affects the risk of chronic diseases
4 What Drives Our Food Choices? We choose foods for many other reasons beyond the basic need to obtain nutrients:TasteEthnic heritage or traditionSocial interactionsAdvertisingAvailability, Convenience, and EconomyHabitsEmotional ComfortBody Weight and imageNutrition and Health Benefits
5 The Nutrients We need to eat and drink to obtain: Nutrients: chemical compounds in foods to provide fuel for energy (measured in kilocalories), growth, maintenance and to regulate body processesSix classes: carbohydrates, fats, protein, vitamins, minerals, waterEnergy: The capacity to do work. The energy in food is chemical energy, it can be converted to mechanical energy in the body.Food energy is measured in calories
6 Meet the Nutrients Six classes of Nutrients Water Carbohydrates ProteinFatVitaminsMinerals
7 The Nutrients Chemical composition of Nutrients Organic – contain carbonCarbohydrateProteinLipidsvitaminsInorganic – do not contain carbonWaterminerals
8 The Nutrients Essential nutrients Nutrients a person must obtain from food because the body cannot make them for itself in sufficient quantity to meet physiological needs.Energy yielding nutrients (Macronutrients)The nutrients that break down to yield energy the body can useCarbohydrateFatProtein
9 Energy-Yielding Nutrients Calories and kilocaloriesCalories are units by which energy is measured. Food energy is measured in kilocalories (kcal)Carbohydrate = 4 kcal/gramProtein = 4 kcal/gramFat 9 = kcal/gram
10 Energy from FoodsEnergy density – a measure of the energy a food provides relative to the amount of food (kcal per gram)Lower energy density – provides low kcal per gramHigher energy density - provides high kcal per gram
11 Lower energy density Higher energy density This 450-gram breakfast delivers 500 kcal, for an energy density of 1.1 (500 kcal/450 g = 1.1 kcal/g)Higher energy densityThis 144-gram breakfast delivers 500 kcal, for an energy density of 3.5 (500 kcal/144 g = 3.5 kcal/g)
13 Other Nutrients Minerals Water Vitamins Organic Not energy-yielding Essential nutrientWater-soluble vs. fat-solubleVulnerable to destructionMineralsInorganicIndestructibleWater
14 Dietary Reference Intakes (DRI) Estimated Average Requirements -(EAR)defines the requirement of a nutrient that supports a specific function in the body for half of the healthy population.Recommended Dietary Allowances – (RDA)use the EAR as a baseinclude sufficient daily amounts of nutrients to meet the known nutrient needs of all healthy populations.This recommendation considers deficiencies.
15 Dietary Reference Intakes Adequate Intakes (AI)reflect the average daily amount of a nutrient without an established RDA that appears to be sufficient.Tolerable Upper Intake Level (UL)is a maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects.
16 Energy Recommendations Estimated Energy Requirement –EERaverage daily energy intake to maintain energy balance and good health for population groups.Acceptable Macronutrient Distribution Ranges (AMDR)range of intakes for energy nutrients that provide adequate energy and nutrients and reduce risk of chronic disease.Carbohydrate: 45% - 65%Fat: 20% - 35%Protein: 10% - 35%RDA –Protein - .8g/kilogramBased on weight
17 Facts about the Recommendations Estimates of adequate energy apply to healthy peopleNot optimal intakes for all individualsNutrients are intended to be met through variety of foodsRecommendations apply to average daily intakesDRI serve a unique purpose – to keep population healthy and prevent chronic diseasesEAR – is for groupsRDA – for individuals
18 Nutrition AssessmentWhat happens When a Person Doesn’t Get Enough or Gets Too much of a nutrient or energy?Malnutrition – Any condition caused by deficiency or excess food energy or nutrient intake over time.Undernutrition – Deficient energy or nutrients.Overnutrition – Excess energy or nutrients
19 Nutrition Assessment of Individuals Evaluates the many factors that influence or reflect nutritional health.Historical information regarding diet, health status, drug use, and socioeconomic status is gathered.Anthropometric data measure physical characteristics including height and weight.Physical examinations require skill and reveal possible nutrition imbalances.Laboratory tests detect early signs of malnutrition.
20 Nutrition Assessment of Individuals Stages in Nutrient Deficiency (example is given for iron)Overt is easy to observePrimary deficiency is inadequate dietary intakeSecondary deficiency is caused by disease or drugsSub-clinical deficiency is the early stages of deficiency without outward signsCovert is hidden
22 Nutrition Assessment of Populations National nutrition surveysNational Nutrition Monitoring Program uses survey research to collect data on foods people eat and people’s health status.Data collected is used for nutrition policy, food assistance programs and food supply regulationNational health goalsHealthy People is a national public health initiative under the U.S. Department of Health and Human Services that is published every 10 years.Identifies the most significant threats to healthFocuses efforts on eliminating these threat
27 How Does the Average American Diet Stack Up? Average American diet is high in:SodiumSaturated fatCaloriesAverage American diet is low in:Vitamin ECalciumFiber
28 How Does the Average American Diet Stack Up? Incidence of overweight and obesity is on the rise.65% of American adults and 15% of children (ages 6 to 19) are overweightTake in more calories than neededBurn fewer calories due to sedentary lifestylesResulting in increased rate of type 2 diabetes (especially children), heart disease, cancer, and stroke
30 The Science of Nutrition Observational Research: involves looking at factors in two or more groups of subjects to see if there is a relationship to certain health outcomesEpidemiological research: study of populations of peopleExample: Relationship of sun exposure and incidence of rickets in Norway compared with AustraliaMay be due to other unidentified diet or lifestyle factors
31 The Science of Nutrition Experimental Research: involves at least two groups of subjectsExperimental group: given a specific treatmentControl group: given a placebo (“sugar pill”)Double-blind placebo-controlled experiment is “gold standard.”Neither scientists nor subjects know which group is receiving which treatment.All variables held the same and controlled for both group.Sample size – number of people in the study.
32 The Science of Nutrition Hypothesis – an educated guess to answer a question. For example: “what foods or nutrients might protect against hypertension?” The hypothesis = “Foods low in sodium and high in potassium help reduce risk of hypertension”
33 Controlled Experiments: Scientists use experimental research to test hypotheses. Figure 1.6
34 What’s the Real Deal When It Comes to Nutrition Research and Advice? Newspaper headlines and television news items report results of a single, recent research study.Advice from authoritative health and nutrition organizations is based on:Consensus: the opinion of group of experts based on collection of information
35 Evaluating Media Headlines with a Critical Eye Before making dietary and lifestyle changes based on media reports, read with a critical eye and ask:Was the research finding published in a peer-reviewed journal?Was the study done using animals or humans?Do the study participants resemble me?Is this the first time I’ve heard about this?Wait until research findings are confirmed and consensus reached by reputable health organizations before making changes.
37 Quackwatchers Beware of health quackery and fraud: Promotion and selling of health products and services of questionable validitySales people introduce health fears and make false nutrition claims and unrealistic promises and guarantees.helps consumers identify quackery and fraud.
38 You Can Trust the Advice of Nutrition Experts Registered Dietitian (RD): completed at least a bachelor’s degree at an accredited U.S. college or university and a supervised practice, passed a national exam administered by the American Dietetic AssociationPublic Health Nutritionist: has degree in nutrition but may not be an RD (if didn’t complete supervised practice, not eligible to take ADA exam)Professionals holding advanced degrees in nutritionLicensed dietitian (LD): licensed by state licensing agencies
39 Obtaining Accurate Nutrition Information on the Internet National Institutes of Health (NIH) 10 Questions to consider when viewing a health-related websiteWho runs the site?Who pays for the site?What is the purpose of the site?Where does the information come from?What is the basis of the information?
40 Obtaining Accurate Nutrition Information on the Internet How is the information selected?How current is the information?How does the site choose links to other sites?What information does the site collect about you and why?How does the site manage interactions with visitors?
41 HomeworkFor 5 point extra credit, provide answers to the following questions:What is the World Food DayWho/what organization founded itWhat year was it foundedWhat is the theme for 2007Complete a family Health History worksheetBring a food label to class next timeThe food label must be a food that contains nutrients (Kcal, fat & protein)Must be submitted next class. No exceptions.